1. Field of the Invention
The invention is directed to flowing electrolyte batteries, and in particular to a system for proclusion of electrical shorting for use in association with flowing electrolyte batteries such as zinc/bromine batteries.
2. Background Art
Flowing electrolyte batteries (Znxe2x80x94Br batteries, V-Redox batteries, etc) are well known in the art for their quality of power providing characteristics and their cycling ability. Generally, such batteries rely on the circulation, by pumps, of electrolyte from containment reservoirs to individual stack components. The contribution of the individual stack components to the internal resistance of the stack should be very constant and the same for all of the stacks. However, sometimes differences in the respective resistances of the stacks can occur. For example, the stripping of cells, ring currents and shunt currents all can contribute to creating a difference in the internal resistance of a given stack.
Generally, if one stack differs in internal resistance from the others, it will eventually draw upon the current from one of the other stacks to drive it. That is, the flow of current within the system of stacks will reverse in direction. This is problematic because reversal of current flow ultimately results in an electrical shortage of the stack. Subsequent to shorting are numerous potential deleterious effects, namely, overheating, melting, fires, as well as the ultimate destruction of the entire battery or the device to which the battery supplies energy.
Thus, it is an object of the invention to provide a system to eliminate dangerous and damaging effects of electrical shorting in a flowing electrolyte battery by immediately detecting a reversal in direction of the flow of current.
It is a further object of the invention to provide a mechanism by which the charging of the entire flowing electrolyte battery is ceased upon the detection of a reversal in direction of the flow of current.
It is a further object of the invention to control a flowing electrolyte battery in a safe and reliable manner.
The invention comprises a system for identifying an electrical short in a flowing electrolyte battery. The system comprises: (a) means associated with the flowing electrolyte battery for detecting direction of current flow through the battery, wherein the flow of current in a first direction is indicative of proper current flow and the flow of current in a second direction is indicative of an electrical short within at least a portion of the battery; and (b) means for ceasing current flow upon detection of current flow in the second direction.
In a preferred embodiment, the flow detection means includes a device capable of sensing an electro-magnetic field associated with at least a portion of the battery. In such an embodiment, the flow detection means is associated with at least one electrical conduit associated with the flowing electrolyte battery. The electrical conduit may comprise a wire or a cable.
In another embodiment, the flow detection means includes a ring sensor.
In yet another embodiment, the flow detection means includes as least one of a digital or analogue sensor.
In still another embodiment, the system further includes means for identifying the direction of current flow.
In a preferred embodiment, the identifying means includes an audible signal upon detection by the detecting means of the flow of current in the second direction.
In another embodiment, the identifying means includes a visual signal upon detection by the detecting means of the flow of current in the second direction.
In yet another embodiment, the identifying means includes an audible signal and a visual signal upon detection by the detecting means of the flow of current in the second direction.
In a preferred embodiment, the means for ceasing the flow of electric current comprises at least one of an electrical, electro-mechanical or mechanical switch.
In another aspect of the invention, the system for identifying an electrical short in a flowing electrolyte battery comprises: (a) means associated with the flowing electrolyte battery for detecting direction of current flow through a battery, wherein the flow of current in a first direction is indicative of proper current flow and the flow of current in a second direction is indicative of an electrical short within at least a portion of the battery; (b) means for ceasing current flow upon detection of current flow in the second direction; and (c) means for identifying the direction of current flow.